Sleeved filter for a breathing circuit

ABSTRACT

A sleeved filter apparatus prevents germs from becoming resident on both the interior and exterior of a breathing device. The sleeved filter apparatus includes a filter member and a sleeve member. The filter member is composed of a first and second enclosure half which are sealed on their interior ends. The external ends of the two enclosure halves have connectors for connecting the sleeved filter apparatus to a breathing device and/or a patient airway component. A filter element is disposed inside the filter member enclosure for preventing gases from flowing between the first connector and the second connector of the filter member without passing through the filter element. This filter member prevents germs from passing between the patient and the interior of the breathing device. The sleeve member is made of a flexible material, and has a first open end, a second open end, and a middle portion extending between the first open end and the second open end. The first open end of the sleeve member is sealingly engaged to the filter member. The sleeve member has a diameter sized to surround the breathing circuit, and a length sufficient to extend along most or all of the entire length of the breathing circuit. The sleeve member prevents germs and bacteria from passing between the patient and the exterior of the breathing device. The sleeved filter apparatus is removable between procedures to permit reuse of the breathing circuit without substantial cross-contamination between patients.

This is a continuation of application Ser. No. 08/925,116 filed Sep. 8,1997 now U.S. Pat. No. 5,901,705.

TECHNICAL FIELD OF INVENTION

The present invention relates to breathing circuits of the type used inanesthesia and respiratory-type devices and more particularly, to atubular sleeve and filter combination for such a breathing circuit.

BACKGROUND OF THE INVENTION

Breathing circuits have been used in the anesthesia field for many yearsto provide a vehicle for transferring anesthesia gas from an anesthesiamachine to a patient, and to transfer exhaled gas from the patient tothe anesthesia machine. Currently, two primary types of breathingcircuits are used. The first type is known as a dual-limb circuit. Sucha device includes an expiratory tube and an inspiratory tube that areusually connected to a `Y` connector. The `Y` connector is then coupled,at its patient end, to an anesthesia face mask or an endotracheal tube.The machine end of the inspiratory tube is coupled to the inspiratoryport of either an anesthesia machine, or to a carbon dioxide absorberthat is attached to an anesthesia machine. The machine end of theexpiratory tube is attached to either the anesthesia machine, or to acarbon dioxide absorber attached to an anesthesia machine. An example ofa carbon dioxide absorber is shown in Komesaroff U.S. Pat. No.5,666,669, that issued on Oct. 22, 1996.

The other type of circuit is a "unilimb" circuit. An example of aunilimb circuit is shown in Leagre and Burrow U.S. Pat. No. 5,404,873and Fukunaga U.S. Pat. No. 4,265,235. A unilimb breathing circuitincludes an expiratory tube and an inspiratory tube that are coupled ina coaxial relation. Usually, the inspiratory tube is disposed within theinterior of the expiratory tube. A patient end connector is provided forcoupling the patient end of the unilimb breathing circuit to either ananesthesia face mask or an endotracheal tube. The machine end of theunilimb circuit contains a coupler having an inspiratory coupler and aseparate, expiratory coupler. The inspiratory coupler is coupled to theinspiratory port of a carbon dioxide absorber or anesthesia machine, andthe expiratory coupler is coupled to the expiratory port of theanesthesia machine or carbon dioxide absorber. The inspiratory couplerhandles gas from the inspiratory tube, and the expiratory coupler endhandles gas from the expiratory coupler.

Both the inspiratory and expiratory tubes function in a similar manner.Anesthesia gas and oxygen are directed into the inspiratory tube, wherethe gases travel from the machine end of the inspiratory tube to thepatient end. The gases are then inhaled by the patient. When the patientexhales, his expiratory gases flow into the expiratory tube, whichconveys the gases back to the carbon dioxide absorber. Within the carbondioxide absorber, carbon dioxide is "scrubbed" from the gases to removeit from the gas stream. The expiratory gas may be then routed back intothe inspiratory tube for rebreathing by the patient. Of course, it isoften advisable to add oxygen and/or anesthesia gas to the rebreathedexpiratory gas, to increase the oxygen and/or anesthesia content of therecycled gas being inhaled by the patient.

Devices which cover the exterior of a breathing circuit are known. Forexample, Smith U.S. Pat. No. 5,377,670 discloses a casing whichsurrounds a breathing circuit tube to define an insulating dead airspace between the breathing tube and the casing for purposes oftemperature retention.

One difficulty encountered with all breathing circuits is that viruses,bacteria and other germs become resident on the breathing circuit duringuse by a patient. To avoid cross-infection, the breathing circuit shouldnot be used by a second patient without sterilization between uses. Tohelp eliminate this risk of cross infection, the breathing circuit canbe designed to be a "single use" breathing circuit that is discardedafter a single use. An alternate way to avoid cross infection is tosterilize and autoclave the "re-usable" breathing circuit after eachuse.

Both of these methods have drawbacks. Autoclaving a breathing circuitafter each use can result in substantial labor and processing costs.Although discarding the breathing circuit after a single use is veryeffective in preventing cross infection, single use circuits can resultin additional costs to the hospital.

Another method for dealing with cross infection is to place a filter onthe breathing circuit for filtering out bacteria and viruses, thuspreventing them from becoming resident within the breathing circuit.Such filters typically act to prohibit such bacteria and viruses frombecoming resident on the interior of the breathing circuit. The filteritself, upon which the bacteria and virus have become resident, can thenbe discarded after single patient use. Through this procedure, thebreathing circuit can be reused, although the filter must be eitherdisposed of or re-sterilized.

Although such breathing filters have proven effective in preventingbacteria and viruses from becoming resident on the interior of theinspiratory and expiratory tubes of the breathing circuits, typicalfilters do nothing to prevent bacteria and viruses from becomingresident on the exterior of the breathing circuit.

Pre-operatively or peri-operatively, blood and other bodily fluids oftenbecome discharged or transferred (via the practitioner's hands) from thepatient being operated on, to the medical equipment and personnel withinthe surgical theater. These bodily fluids contain a wide variety ofbacteria and viruses that are not visible to the naked eye. If thebodily fluids, and hence the viruses and bacteria, make contact with theexterior of the breathing circuit, they will become resident on thebreathing circuit, and thus have the potential to cross-infect anotherperson.

As a goal of modem surgical practice is to provide a substantially "germfree" environment, the presence of such bacteria and viruses on theexterior of the breathing circuit is undesirable, and hampers theability of the circuit to be reused without sterilization. By preventingbacteria and viruses from becoming resident both on the interior andexterior of the breathing circuit tubes, one would enable a breathingcircuit to have the potential to be reused for multiple patients,without incurring a substantial risk of cross infection among patients.

It is therefore an object of the present invention to provide anapparatus for helping to prevent bacteria and viruses from becomingresident on both the interior surfaces and exterior surfaces of ananesthesia breathing circuit.

SUMMARY OF THE INVENTION

In accordance with the present invention, a sleeved filter apparatus isprovided for preventing germs from becoming resident on both theinterior and exterior of a breathing device. The sleeved filterapparatus comprises a filter member having a hollow interior, a firstconnector and a second connector. A sleeve member has a first open end,a second open end and a middle portion extending between the first openend and the second open end. The first open end of the sleeve member issealingly engaged to the filter member.

Preferably, the filter member is designed to be connected to a breathingdevice, which may comprise a tubular breathing circuit having a patientend connector and a machine end connector. The first connector of thefilter member is preferably sized and shaped for being coupled to eitherthe patient end connector and/or the machine end connector of thebreathing circuit.

The sleeve member is preferably comprised of a flexible material, andhas a diameter that is sized to loosely surround, and contain the tubeor tubes of the breathing circuit. Although a sleeve for use with aunilimb circuit should have a generally constant diameter throughout itslength, a sleeve designed for use with dual limb breathing circuitsshould have an expanding diameter throughout its length.

The filter member is connected to the breathing device, which may be abreathing circuit, using one of the filter member connectors. The otherfilter member connector could be attached to an anesthesia face mask, oran endotracheal tube. Preferably, the tubular sleeve extends alongsubstantially the entire length of the breathing circuit, or at least somuch of the length as is likely to come into contact with bodily fluids.The first end of the tubular sleeve is preferably bonded to form a sealwith the filter, and is fabricated to be permanently connected to thefilter member.

To attach the filter/sleeve device to an anesthesia breathing circuit,the breathing circuit port of the filter member is coupled onto thepatient end connector of the anesthesia breathing circuit. The tubularsleeve is then pulled over the length of the breathing circuit. After anoperation or procedure with a particular patient, the filter can then beremoved, by disconnecting it from the patient end of the anesthesiabreathing circuit. As the tubular sleeve is connected to the filter,pulling the filter out of engagement with the breathing circuit, andaway from the breathing circuit, also pulls the tubular sleeve off thebreathing circuit. The filter and tubular sleeve can then be discarded,and a new sleeved filter inserted onto the anesthesia breathing circuitfor use with the next patient.

One feature of the present invention is that the filter helps to preventbacteria and viruses from becoming resident on the interior of thebreathing circuit, and the tubular sleeve helps to prevent bacteria andviruses from becoming resident on the exterior of the breathing circuit.By removing the filter and tubular sleeve from the breathing circuitafter a procedure, the bacteria and viruses, which become residentprimarily within the filter and on the exterior surface of the tubularsleeve, can then be discarded by discarding the tubular sleeve andfilter. This leaves the breathing circuit in a sufficientlybacteria-free and virus-free condition to permit reuse of the breathingcircuit by another patient.

Another feature of the present invention is that the sleeved filterapparatus of the present invention can be made relatively inexpensively,when compared to the costs of other components which typically comprisea full breathing set. Full breathing sets consist of several components,many of which are not economically feasible to either discard orsterilize after each use. The sleeved filter device will filter bacteriaand viruses that are carried in the patient's breath, thus preventingthe bacteria and viruses from becoming resident on the interior of thebreathing device components. The sleeve, which can be sized toaccommodate various types of breathing device designs, will interceptbodily fluids and other contaminants that would otherwise contact theexterior of the breathing device components. As the sleeved filter canbe made relatively inexpensively it can be disposed of after each usecost effectively, while permitting the relatively more expensivecomponents of the breathing device to be re-used, and while stillprotecting patients from cross-contamination.

Another feature of the present invention is that it will help reduce theclutter caused by breathing devices. Many breathing devices have severallimbs running between the patient and the breathing device. The sleevemember of the present invention will surround all of these limbs andeffectively create one limb running between the patient and thebreathing device, thus reducing clutter and space requirements.

These and other features of the present invention will become apparentto those skilled in the art upon a review of the detailed descriptionpresented below in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a unilimb type of breathing circuit towhich is attached a sleeved filter of the present invention;

FIG. 2 is an elevational view of a filter and sleeve, wherein the sleeveis compressed for facilitating placement of the sleeve onto thebreathing circuit;

FIG. 3 is an alternate embodiment sleeved filter of the presentinvention especially adaptable for use with dual-limb breathingcircuits; and

FIG. 4 is a sectional view of a filter useable with the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

FIGS. 1 and 2 show a breathing circuit 10 having a media containermember, such as a filter member 12 and sleeve member 14 of the presentinvention attached thereto. The breathing circuit 10 shown in FIG. 1 isgenerally identical to the breathing circuit shown in Leagre and BurrowU.S. Pat. No. 5,404,873. The breathing circuit 10 includes aninspiratory tube 20 and an expiratory tube 22. As the breathing circuit10 is a unilimb type breathing circuit, the expiratory tube 22 andinspiratory tube 20 are disposed coaxially with each other, with theinspiratory tube 20 being disposed within the interior of the expiratorytube 22.

Preferably, each of the inspiratory tube 20 and expiratory tube 22include generally corrugated middle portions, which help to prevent thetubular portions of the expiratory tube 22 and inspiratory tube 20 fromkinking when bent or twisted.

The breathing circuit 10 includes a patient end connector 24 and amachine end connector 26. The patient end connector 24 is provided forbeing coupled to the filter member 12. The machine end connector 26 isprovided for connecting the breathing circuit 10 to an anesthesiamachine (not shown), a ventilator (not shown), or to a carbon dioxideabsorber (not shown) that is attached to an anesthesia machine. Themachine end connector 26 includes an inspiratory port connector 42 whichcan be coupled to the inspiratory port of either the anesthesia machineor the carbon dioxide scrubber. The inspiratory port connector 42 iscoupled directly to the inspiratory tube 20. The machine end connector26 also includes an expiratory port connector 44 which can be coupled toa bendable gas tube 46. Bendable tube 46 includes a connector 48 forcoupling the bendable tube 46 to the expiratory port of an anesthesiamachine or a carbon dioxide absorber. The bendable tube 46 andexpiratory port connector 44 are provided for conducting expiratory gasfrom the interior of the expiratory tube 22.

As best shown in FIGS. 2 and 4, the breathing filter member 12 ispreferably made from a three piece construction that includes agenerally part frusto-conically, part cylindrically-shaped first member60, a generally part frusto-conically, part cylindrically-shaped secondmember 62, and a generally disk-shaped filter element 64 which isdisposed in the interior of the breathing filter member 12. In certainfilters, a heat and moisture exchange (HME) media 69 is also disposedwithin the interior of the filter member 12.

The first member 60 includes a first connector 36 which is sized andshaped for being received by the patient end connector 24 of thebreathing circuit 10. The frusto-conical portion 70 of the first member60 terminates in the cylindrical portion 73. The cylindrical portion 73terminates in a female lip 72.

The first member 60 may also contain a luer-lock connector 61 having aremovable cap 63. Connector 61 has a hollow interior for placing theinterior of the filter 12 in gaseous communication with a gas samplingline 67 (FIG. 1) that can be attached to the filter (via the connector61), for the purpose of monitoring the patient's expired gasses, andthus monitoring the patient's physical condition. A solid post 65 canalso be provided for providing a holder for cap 63. When the gas line 67is connected to the connector 61, the gas line is positioned adjacent tothe exterior of the breathing circuit 20 along its length, but withinthe interior of the sleeve 14. The distal end of the gas line 67includes a cap 87 having an opening through which the gas line 67 canpass. The cap 87 is provided for coupling the distal end of the gas line67 to the connection 61, and hence to the interior of the filter 12. Thegas line 67 should be at least as long as the length of the breathingcircuit 20, so that the proximal end 89 of the gas line 67 may emergefrom the interior of the sleeve adjacent the open end of the sleeve 14,which is adjacent to the machine end of the breathing circuit, to thuspermit the proximal end 89 to be coupled to a gas sampling apparatus.

Second member 62 is generally similar in shape to first member 60, andincludes a second connector 76; and a cylindrical portion 77; and afrusto-conical portion 78. The cylindrical portion 77 terminates in anmale lip member 80 which is sized for being received snugly by femalelip 72.

Second connector 76 is provided for connecting to a patient device, suchas an anesthesia breathing mask (not shown), angle connector, anendotracheal tube (not shown) or other artificial airway device (notshown).

The first and second members 60, 62 of the filter member 12 are joinedtogether so that the male and female lips 72, 80 engage snugly. In orderto maintain the lips 72, 80 in engagement, the lips can be sonicallywelded, or bonded together. When the first and second members 60, 62 areso joined, they define a generally hollow interior 84. The disk-shapedfilter element 64 and HME media 69 is disposed to extend radially in theinterior 84 of the filter member 12, adjacent to the mated lips 72, 80.As shown in FIG. 4, the HME media 69 fills most of the interior 84 ofthe second member 62. The interior surface of the frusto-conical portion70 of the second member includes a plurality of axially extending fins85 for maintaining the HME media 84 in a spaced relation from theinterior surface of the frusto-conical portion 70.

The filter element 64 and HME media 69 are sized to fit snugly againstthe lips 72, 80 so that any gases passing through the interior 84 of thefilter member 12, between the first 36 and second 76 connectors, willpass through the filter element 64 and HME media 69. The filter element64 is chosen to be of a type that is capable of trapping bacteria,viruses and other germs of interest thereon. Preferably, the filtermember 12 should trap bacteria and viruses flowing in both directions.For example, bacteria and viruses that are resident in the patientshould be trapped on the side of the filter element 64 adjacent tosecond connector 76, to thereby prevent the patient's bacteria andviruses from flowing into the inspiratory tube 20 and ultimately (in arebreathing application) into the expiratory tube 22. Similarly, anybacteria or viruses that are resident in the interior of either theinspiratory tube 20 or expiratory tube 22 should be trapped on thesurface of the filter element 64 adjacent to first connector 36, toprevent any such bacteria or viruses from finding their way into thepatient (not shown).

Through this trapping of bacteria and viruses, it will be appreciatedthat the filter member 12, and in particular filter element 64 willprevent the transfer of many viruses and bacteria between the patientand the breathing circuit 10. By preventing the transfer of such virusesand bacteria, the breathing circuit 10 will help to reduce the transferof bacteria and viruses between patients, if the breathing circuit 10 isused on multiple patients, so long as the filter member 12 is replacedfor each new patient. An example of a filter that will function with thepresent invention is the Virobac II model filter that is manufactured byKing Systems, the assignee of the instant application.

The HME media 69 is preferably chosen to be able to hold and retainmoisture. An example of an HME media 69 that will function in thepresent invention is the Edith AME product manufactured byDatex-Engstrom of Bromma, Sweeden.

The sleeve member 14 has a first end 100 that is effectively closedthrough its attachment to the exterior surface of the filter member 12,adjacent to the lips 72, 80 of the filter member 12. The sleeve member14 also includes a second, open end 102 that, when attached to abreathing circuit 10, is disposed adjacent to the machine end connector26 of the breathing circuit 10. A middle portion 104 of the sleevemember 14 extends between the first end 100 and the second end 102. Thetubular sleeve 14 includes an exterior wall surface 108, and an interiorwall surface 110, which defines the sleeve 14.

Preferably, the sleeve member 14 is constructed of a clear, flexiblematerial to enable the medical practitioner to view the expiratory andinspiratory tubes 20, 22 and easily manage the entire circuit 10.Additionally, the sleeve member 14 should be constructed of alight-weight, relatively inexpensive material, to help minimize thecosts of producing the sleeve member 14. It has been found by applicantthat a clear, extruded type polyethylene, polypropylene or polyvinylfilm, having a thickness generally similar to a heavy duty plastic foodstorage bag will perform admirably in this role as a sleeve member 14.

The first end 100 of the sleeve member 14 is preferably attached to theexterior surface of the filter member 12, adjacent to the lips 72, 80.The diameter of the sleeve member 14 adjacent to the first end 100should be sized to receive the filter member 12 snugly. Preferably, thefirst end 100 is joined to the filter element 12, by glue, tape, orbonding of some type. Alternately, the first end 100 can be sized forbeing received between the male and female lips 72, 80 of the filterelement 12, so that the first end 100 becomes sandwiched between thelips 72, 80 to help maintain the position of the first end 100 of thesleeve member 14 on the filter element 12. After the lips 72, 80 andfirst end 100 are so sandwiched together, they can be bonded together,such as by sonic welding, glue or frictional engagement. Alternately,mechanical bonding techniques, such as adhesive tape, or matingprotrusions and apertures formed in the respective male 80 and female 72lips can be used to bond the lips 72, 80 and first end 100.

In any event, the goal is to ensure that the first end 100 is securelyattached to the filter element 12, in a manner that will prevent thefirst end 100 from becoming dislodged from the filter element 12.

As alluded to above, the material from which the sleeve 14 is madeshould be a material which will provide a germ barrier, for preventingviruses and bacteria from passing through the exterior wall surface 108,into the interior of the sleeve 14, and likewise preventing bacteria andviruses from passing through the interior wall surface 110 to theexterior of the sleeve 14. The plastic materials discussed above willgenerally perform this function.

The purpose of the exterior wall surface 108 is to catch any viruses orbacteria that may fall thereon to prevent these viruses and bacteriafrom contacting the exterior wall 111 of the relatively exteriorlyexposed expiratory tube 22. In this regard, it will be appreciated thata barrier need not be present to prevent bacteria or viruses fromfalling on the exterior surface of the inspiratory tube 20, as theexpiratory tube 22 performs this function already.

The tubular sleeve 14 which is intended for use with a unilimb typecircuit has a generally constant diameter D--D throughout its length,except perhaps that portion of its length adjacent to its first end 100,where it may be either slightly enlarged, or have a reduced diameter forsnugly fitting onto the filter member 12. Preferably, the diameter D--Dshould be great enough to enable the sleeve 14 fit relatively looselyaround the expiratory tube 22, to permit the sleeve 14 to be slid overthe expiratory tube 22, but not so loosely that it gets in the way. Assuch, the diameter D--D of the sleeve 14 should be somewhere between0.25" and about 2" greater than the diameter of the expiratory tube 22.Since the filter member 12 has a diameter greater than the diameter ofthe expiratory tube 22, a sleeve 14 having a diameter generally similarto the diameter of the widest part (adjacent lips 72, 80) of the filtermember 12 will work well as the diameter D--D of the entire length ofthe sleeve member 14.

The sleeve member 14 also has a length which extends between its firstend 100 and its second end 102. The length should be chosen to covermost (if not all) of the length of the breathing circuit 10, up to theexpiratory port connector 44, over which the sleeve member 14 cangenerally not pass. Due to the relatively thin, flexible nature of thesleeve member 14, its length can be greater than the length of thebreathing circuit 10, with the excess being "bunched up" adjacent to theexpiratory connector 44. Preferably, the sleeve 14 has a length ofbetween about 40 inches and 120 inches, which corresponds to a lengthequal to or slightly greater than the standard relaxed lengths ofunilimb breathing circuits.

Turning now to FIG. 2, it will be noticed that the sleeve member 14 isgenerally somewhat bunched up. This is the position that the sleevemember 14 would preferably be in prior to its attachment to thebreathing circuit 10. To place the filter member 12 and sleeve member 14onto a breathing circuit 10, the sleeve member 14 is bunched up as shownin FIG. 2. The open end 102 is slid over the patient end connector 24 ofthe breathing circuit 10. Returning now to FIG. 1, filter member 12 isthen pushed toward the patient end connector 24, as the sleeve member 14is pulled over the breathing circuit 10, to a point wherein the firstconnector 36 of the filter member 12 can be coupled to the patient endconnector 24 of the breathing circuit 10. The second end 102 is thenpulled along the breathing circuit 10, until the sleeve member 14 iseither stretched to its full length, or else the second end 102 contactsthe expiratory connector 44.

To remove the device, one can grab the filter member 12, in a positionadjacent to the first end 100 of the sleeve, and pull the filter member12 away from the patient end connector 24, to separate the firstconnector 36 of the filter member 12 from the patient end connector 24.When disconnection is achieved, the filter member 12 can then be pulledin a direction away from the patient end connector 24. As the filtermember 12 is coupled to the first end 100 of the sleeve member 14, thepulling of the filter member 12 away from the patient end connector 24,will pull off the middle portion 104 and second end 102 of the sleevemember 14 from the breathing circuit 10, to effect the removal of thefilter member 12/sleeve member 14 combination from the breathing circuit10.

During use, the exterior wall surface 108 of the sleeve member 14 ispositioned over the exterior surface of the expiratory tube 22 in amanner that permits it to stop any virus and bacteria containing bodilyfluids (or other virus or bacteria containing materials) from reachingthe exterior surface 108, thereby preventing any such fluids or othermaterials from contacting the exterior surface of the expiratory tube22, thus helping to maintain the exterior surface of the expiratory tube22, and hence the breathing circuit 10, in a relatively germ-free state.Additionally, if viruses and bacteria are already resident on theexterior surface of the expiratory tube, the placement of the sleevemember 14 over the expiratory tube 22 helps to prevent any such virusesor bacteria from being transferred throughout the operating theater (orpatient room), to thereby help to prevent any such viruses or bacteriathat are resident on the exterior of the expiratory tube 22 from cominginto contact with the patient or medical personnel, and not impactingtheir health.

An alternate embodiment filter member 240 and sleeve member 248 deviceis shown in FIG. 3. In FIG. 3, the filter member 240 is generallysimilar to filter member 12 shown in FIGS. 1 and 2, but the sleevemember 248 is configured somewhat differently, to accommodate adual-limb breathing circuit 200. Dual-limb breathing circuit 200contains an inspiratory tube 210 having a patient end connector 212, anda machine end connector 214. The inspiratory tube 210 includes asinge-lumen tube portion 215 which is disposed between the patient endconnector 212 and the machine end connector 214. The dual-limb breathingcircuit 200 also includes an expiratory tube 216 having a patient endconnector 218, and a machine end connector 220, with a single-lumen tubeportion 219 extending between the patient end connector 218 and machineend connector 220.

Dual-limb breathing circuits of the type described above are well knownin prior art, and pre-date the unilimb breathing circuits of the typedescribed in FIGS. 1 and 2. A `Y` component 230 is provided forconnecting the patient end connectors 212, 218 of the inspiratory tube210 and expiratory tube 216 to the filter 240. The `Y` tube 230 includesa first connector 232 for mating onto the patient end 212 of theinspiratory tube 210, and a second connector 234 for mating onto thepatient end 218 of the expiratory tube 216. The `Y` tube also includes athird connector 236 for mating onto the first connector 242 of thefilter member 240. As discussed above, the filter member 240 of theembodiment shown in FIG. 3 may be identical to the filter member 12 ofthe embodiments shown in FIGS. 1 and 2. The filter member 240 alsoincludes a second connector 244, and a filter element, and possibly HMEmedia (e.g., HME media 69 in FIG. 4), that is disposed in the interiorof the filter member 240.

The sleeve member 248 includes a relatively, reduced diameter first end250 which is preferably sealingly engaged to the filter member 240 in amanner similar to the manner in which the first end 100 of sleeve 14 issealingly engaged to the filter member 12 of the embodiment shown inFIGS. 1 and 2. The sleeve member 248 also includes a second, open end252, and a middle portion 249 which extends between the first end 250and the second end 252. The sleeve member 248 can be made from materialgenerally identical to the material discussed above in connection withsleeve member 14 of the embodiment shown in FIGS. 1 and 2. The sleevemember 248 has an exterior wall surface 249 and an interior wall surface260 which define a generally hollow interior 256 for receiving theinspiratory and expiratory tubes 210, 216 respectively.

Because the inspiratory and expiratory tubes 210, 216 of the dual-limbcircuit are not collinear, as they are in the unilimb circuit 10 of FIG.1, the diameter D--D of the sleeve must be greater to accommodate therelatively greater bulk of the dual-limb breathing circuit 200. Thesleeve member 248 also has a length L which is defined as that lengthbetween the first end 250 of the sleeve 248, and the second end 252 ofthe sleeve member 248.

In the embodiment shown in FIG. 3, the sleeve member 248 has a generallyconstant diameter throughout the majority of its length, except for thatportion adjacent to the first end 250 of the sleeve member 248, whichhas a relatively reduced diameter. Alternately, the sleeve member 248can be designed to have a diameter which increases as one moves from thefirst end 250 to the second end 252, thus giving the sleeve member 248 asomewhat "A" shaped or frusto-conical configuration. For example, thefirst end 250 of the sleeve member 248 can have a diameter of betweenabout 2 inches and 3 inches, which expands outwardly along the length ofthe sleeve member 248, so that the second end 252 of the sleeve member248 has a diameter of between about 5 inches and 8 inches. Preferablythe sleeve member 248 has a length of between about 40 inches and 120inches, which corresponds to a length similar, or slightly longer thanthe standard relaxed lengths of expiratory and inspiratory tubes 210,216.

However, it will also be appreciated that one function that can beserved by the sleeve member 248 is to keep the inspiratory tube 210 andexpiratory tube 216 in close proximity throughout the majority of theirlength. By keeping the inspiratory tube 210 and expiratory tube 216 inclose proximity, the sleeve member 248 can help reduce clutter in theoperating theater, of the type that normally occurs when one uses adual-limb circuit.

From a virus and bacteria barrier standpoint, sleeve member 248 performsits function in a manner generally similar to the manner in which sleevemember 14 of FIGS. 1 and 2 performs its function. Further, sleeve member248 and filter member 240 may be attached to, and detached from thedual-limb breathing circuit 200, in a manner generally similar to thatdiscussed above in connection with the embodiments of FIGS. 1 and 2.

Having described the invention in detail, it will be appreciated thatsome modifications exist within the scope and spirit of the invention.

What is claimed is:
 1. A sleeved breathing filter apparatus forpreventing contamination of both the interior and exterior of abreathing device, the sleeved filter breathing apparatus comprising:afilter container member having a hollow interior, a first connector, asecond connector and a filter element disposed within the hollowinterior such that gases passing between the first connector and thesecond connector must pass through the filter element, the firstconnector capable of being connected to and disconnected from thebreathing device by the user at the site of use; and a tubular sleevemember having a first end and a second end, the first end beingsealingly engaged to the filter container member, the tubular sleevemember and the second end thereof capable of being expanded by the userat the site of use to loosely surround a portion of the breathingdevice; whereby, when a contamination source is operably connected tothe second connector and the breathing device is operably connected tothe first connector, contaminants passing through the second connectorare substantially prevented from contacting the interior of thebreathing device by the filter element and contaminants passing aroundthe second connector are substantially prevented from contacting theexterior of the breathing device by the sleeve member.
 2. The sleevedbreathing filter apparatus of claim 1, wherein the filter containermember includesa first enclosure half having an external end and aninternal end, the external end including the first connector of thefilter container member; a second enclosure half having an external endand an internal end, the external end including the second connector ofthe filter container member; the internal end of the first enclosurehalf being sealingly connected to the internal end of the secondenclosure half.
 3. The sleeved breathing filter apparatus of claim 2whereinthe internal end of the first enclosure half has a female liphaving a larger diameter than the external end of the first enclosurehalf, the internal end of the second enclosure half has a male liphaving a larger diameter than the external end of the second enclosurehalf, the internal end of the first enclosure half being sealinglyconnected to the internal end of the second enclosure half by mating thefemale lip of the first enclosure half with the male lip of the secondenclosure half, the filter element extending radially in the interior ofthe filter container member, and the filter element being sized to fitsnugly in the interior of the filter container member and disposedadjacent to the area where the first enclosure half is sealinglyconnected to the second enclosure half.
 4. The sleeved breathing filterapparatus of claim 3 wherein the first end of the sleeve member issealingly engaged to the filter container member by sandwiching thefirst end of the sleeve member between the female lip of the firstenclosure half of the filter container member and the male lip of thesecond enclosure half of the filter container member.
 5. The sleevedbreathing filter apparatus of claim 1, wherein the sleeve member has agenerally constant sleeve diameter.
 6. The sleeved breathing filterapparatus of claim 5, wherein the filter container member includesafirst enclosure half having an external end and an internal end, theexternal end including the first connector of the filter containermember; a second enclosure half having an external end and an internalend, the external end including the second connector of the filtercontainer member; the internal end of the first enclosure half beingsealingly connected to the internal end of the second enclosure half. 7.The sleeved breathing filter apparatus of claim 6, wherein the internalend of the first enclosure half has a female lip, and the internal endof the second enclosure half has a male lip, the internal end of thefirst enclosure half being sealingly connected to the internal end ofthe second enclosure half by mating the female lip of the firstenclosure half with the male lip of the second enclosure half, and thefirst end of the sleeve member being sealingly engaged to the filtercontainer member by sandwiching the first end of the sleeve memberbetween the female lip of the first enclosure half and the male lip ofthe second enclosure half.
 8. The sleeved breathing filter apparatus ofclaim 1, wherein the sleeve member has a sufficient length between thefirst end and the second end so that the sleeve member can extend alongsubstantially the entire length of the breathing device.
 9. The sleevedbreathing filter apparatus of claim 1, wherein the sleeve member has afirst section adjacent to the first end and a second section adjacent tothe second end; the first section having an increasing diameter whichincreases as the first section gets further from the first end, thesecond section and second end having a generally constant diameter equalto the maximum diameter of the first section, whereby, when a multi-limbbreathing device is connected to the second connector, the generallytubular sleeve and second end of the sleeve member loosely surround themulti-limb breathing device.
 10. The sleeved breathing filter apparatusof claim 9, wherein the filter container member includesa firstenclosure half having an external end and an internal end, the externalend including the first connector of the filter container member; asecond enclosure half having an external end and an internal end, theexternal end including the second connector of the filter containermember; the internal end of the first enclosure half being sealinglyconnected to the internal end of the second enclosure half.
 11. Thesleeved breathing filter apparatus of claim 10, wherein the internal endof the first enclosure half has a female lip, and the internal end ofthe second enclosure half has a male lip, the internal end of the firstenclosure half being sealingly connected to the internal end of thesecond enclosure half by mating the female lip of the first enclosurehalf with the male lip of the second enclosure half, and the first endof the sleeve member being sealingly engaged to the filter containermember by sandwiching the first end of the sleeve member between thefemale lip of the first enclosure half and the male lip of the secondenclosure half.
 12. The sleeved breathing filter apparatus of claim 1,wherein the first end of the sleeve member has a first diameter, and thesecond end of the sleeve member has a second diameter, the seconddiameter being greater than the first diameter.